Most people don’t know that there are only approximately fifty active diamond mines in the entire world. Most of these mines are not located on the outskirts of major towns or cities; instead, they are situated in remote locations amid extremely harsh environments. However, these mines still do a wonderful job at discovering rare and unique diamonds with exceptional properties. Diamonds can be defined as crystallized carbon formed from a primary carbon source, after being subjected to extreme pressure and temperature.
Most of the commercially minable diamonds are found at a certain depth in the mantle of the earth, which is estimated to be approximately 150 kilometers beneath the surface. This area is often called as the diamond stability zone, and the temperature here is estimated to be around 1000 degree Celsius. The pressure here is pretty high too, clocking at around 60 kilobars. The formation of a diamond takes somewhere between one to over three billion years under these conditions.
In some rare cases, diamonds may also form within in rocks, which are sub ducted deep into the mantle of the earth as a result of plate tectonic processes. These types of movement dramatically increase the pressure, but the temperature continues to be relatively low, that is, at around 200 degree Celsius or so.
Another interesting thing to note is that diamonds and other gemstones may also come to earth from outer space. Some of the meteorites that come from the outer space enter into our atmosphere and strike the surface, which in turn results in the deposition of natural diamonds. It is interesting to note that diamonds that are deposited as a result of this process are relatively rare, which is why so many people are ready to spend huge fortunes to get just one of these “space diamonds”.
Diamonds that are formed in the diamond stability zone of earth’s mantle make their way to the surface through violent volcanic eruptions, which happen deep inside the mantle. These eruptions pass through the diamond stability zone and carry the diamonds with them to the surface of the earth. In some cases, they may result in tremendous explosions that people can actually see, although only in some regions. If that is the case, then diamonds can get spread across a wide area.